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Although there is evidence that St John’s wort may be of benefit in mild or moderate depression, practitioners should:
• not prescribe or advise its use by people with depression because of uncertainty about appropriate doses, persistence of effect, variation in the nature of preparations and potential serious interactions with other drugs (including oral contraceptives, anticoagulants and anticonvulsants)
• advise people with depression of the different potencies of the preparations available and of the potential serious interactions of St John’s wort with other drugs.

Funny that. In the last issue of EBMH, Edzard Ernst, the professor of complementary medicine who has become the bête noire of the alternative medicine crowd was less dismissive. Reviewing the latest Cochrane update he concludes that there is now plenty of evidence demonstrating that SJW is an effective antidepressant and if you can avoid herb-drug interactions, it may be safer than conventional drugs. So why don’t we recommend SJW for depression?

I have written about SJW here before and was less than complimentary (ouch!). My scepticism was similar to the NICE position: you can’t be sure what you are getting, and patients thinking that it’s not really a drug mix it with prescription medication and run into trouble. Perhaps, however, there is more to it than that. Given the rather murky history of clinical trials and marketing with conventional antidepressants and the often marginal benefit over placebo it does seem as though when it comes to evidence we hold St John’s wort to a higher standard. Trawl through the rapid responses of a trial involving SJW and you will find a degree of nit-picking that is rarely seen with the SSRIs. This type of reader or reviewer bias is not much discussed and competing interest statements rarely include declarations of inherent prejudice. In this editorial for Clinical Evidence, Professor Ernst criticises the knee-jerk assumption that if a clinical trial of a complementary medicine shows efficacy it must be a flawed trial. So is St John’s wort being treated unfairly? The answer, I think, has to be yes.